Abstract: The invention belongs to the technical field of battery management, and in particular relates to a method and apparatus for collecting voltage differential parameters of individual battery cells in a battery pack. In the invention, a reference voltage is provided, the reference voltage is compared with an actual voltage of each individual battery cell at a same moment to obtain a relative voltage difference value between the actual voltage of each individual battery cell and the common reference voltage at the current moment; and an actual voltage difference value between the actual voltage of each individual battery cell and an actual average voltage value of the actual voltages of all individual battery cells is determined according to the relative voltage difference value, and each actual voltage difference value is used for representing the voltage differential parameter of the individual battery cell relative to a battery system.

Abstract: A current source with active common mode rejection uses a principle of having a branch for the generation of the required current, to the output (107) of which one end of the load (3) is connected; and a branch of the active compensation circuit (ACC) (200), to the output (203) of which the other end of the load (3) is connected. By means of at least one input (201) of the ACC (200), at least one signal is sensed on the load, and subsequently it is processed so that the result of processing of at least one signal from at least one input (201) preferentially represents the common mode voltage, which corresponds to the pair of voltages at the voltage terminals (1) and (2) of the load (3), or voltage close to the common mode voltage.

Abstract: A method is provided for current-based detection of an electrical fault in an electrical network of a motor vehicle, the network having at least: one battery, one pulse-controlled inverter, one d.c. voltage converter, and an intermediate circuit associated with the pulse-controlled inverter. The method includes: detecting magnitudes of each a battery current, a d.c. voltage converter current, and an intermediate circuit current; comparing current magnitudes according to provided equations; and checking based on the comparison of whether a specifiable deviation has been exceeded. An alternative method for voltage-based detection of an electrical fault in an electrical network of a motor vehicle includes: detecting magnitudes of each a battery voltage, a d.c. voltage converter voltage, and an intermediate circuit voltage; comparing voltage magnitudes according to provided equations; and checking based on the comparison of whether a specifiable deviation has been exceeded.

Abstract: Measurement devices, systems, and methods to measure a high field conductivity of a fluid are provided herein. The measurement device includes a fluid cell, a pair of electrodes, a voltage switch, and a measurement unit. The fluid cell is on an inclined plane to receive the fluid. The pair of electrodes are connected to the fluid cell. The pair of electrodes are spaced apart from one another to receive the fluid therebetween and positioned parallel to one another to pass an electrical current therethrough. The power unit provides a high voltage power supply to one electrode of the pair of electrodes. The measurement unit measures the electrical current that passes between the pair of electrodes through the fluid.

Abstract: An oscilloscope system includes a current probe, a processing unit and a display unit. The current probe includes a high and low gain signal paths for receiving simultaneously a signal of interest from a device under test (DUT), and to output amplified small and large current portions of the signal of interest, respectively. The processing unit receives first and second digitized data corresponding to the amplified small and large current portions output by the high and low gain signal paths, respectively, and processes the first and second digitized data for display as zoomed-in and zoomed-out waveform data, respectively. The display unit displays simultaneously a zoomed-in waveform in a first display window, based on the zoomed-in waveform data, and a zoomed-out waveform in a second display window, based on the zoomed-out waveform data, using the same time scale. The small current portion is less than a predetermined threshold.

Abstract: A charging device for a power storage device includes a power conduit configured to deliver current to the power storage device and a detection system configured to be coupled to the power conduit. The detection system includes a current control device coupled to the power conduit and configured to control the current delivered to the power storage device. The detection system also includes a test conductor, a current sensor coupled to the test conductor, and a controller coupled to the current sensor by the test conductor. The current sensor is arranged to detect an amount of current within the test conductor and configured to generate a current measurement signal representative of the current detected. The controller is configured to generate a test signal, transmit the test signal through the test conductor, receive the current measurement signal, and determine a status of the detection system based on the current measurement signal.

Abstract: The invention relates to a method for determining a characteristic status parameter of a memory unit via an electric circuit arrangement. In the circuit arrangement at least one inductive component and at least one capacitive component are arranged, forming a tuned circuit with the memory unit. The method has the following steps of energizing the tend circuit by temporary charging of the capacitive component, the energizing being carried out by an energizing device electrically supplied by the memory unit, and determining a time-dependent voltage change at the capacitive component after terminating the energizing and determining the characteristic status parameter from the time-dependence of the voltage change. The invention further relates to a corresponding electrical circuit arrangement and an electrical memory, including such a circuit arrangement.

Abstract: A ground fault detection circuit according to the present invention is a ground fault detection circuit that detects the occurrence of a ground fault of a battery that is insulated, and that includes: an AC signal generation section that generates an AC signal; a first capacitive element that couples the AC signal generated by the AC signal generation section to the battery; a voltage division section that voltage divides the AC signal that is coupled to the battery by the first capacitive element; a ground fault detection unit that detects a ground fault of the battery based on an AC component of an input signal; and a second capacitive element that couples the AC signal that has been voltage divided by the voltage division section to the ground fault detection unit as the input signal.

Abstract: A battery cell measurement system comprising a signal generator coupled to a pulse density modulation circuit generating a control signal which drives a switch connected between a first terminal of a battery cell and a first terminal of a bleeding impedance, a second terminal of the bleeding impedance being coupled to a second battery cell terminal. The first terminal is coupled to a first terminal of a second switch. The second terminal is coupled to a first terminal of a third switch. A second terminal of the second switch and second terminal of the third switch are coupled and are further coupled to a low-pass filter. A signal generated by the low-pass filter is inputted into an analog to digital converter, which provides a signal representative of either a signal across the bleeding impedance, or a signal between the battery cell terminals.

Abstract: In a voltage detecting apparatus, a voltage controlled oscillator, when an input voltage is applied thereto, outputs a signal with a logical value that is periodically inverted. A detector counts a number of logical inversion of the output signal from the voltage controlled oscillator over an interval between edges of pulses of a pulse signal to thereby generate, based on the counted number of logical inversion, digital data as a detected result of the input voltage. A determiner determines whether a reduction of a time required to detect the input voltage is higher in priority than an increase of a resolution of detection of the input voltage. A variably setting unit variably sets a frequency of the pulse signal based on a result of the determination of whether the reduction of the time required to detect the input voltage is higher in priority than the increase of the resolution of detection of the input voltage.

Abstract: A portable computer may include battery indicator light structures. Battery status information in the portable computer may be presented to a user using an array of light-emitting diodes or other light emitters. Light-emitting diodes may be mounted on a printed circuit board. A stiffener may provide the printed circuit board with rigidity. The printed circuit board may include a connector that allows the board to be connected to a main logic board. A switch on the printed circuit board may be actuated by a power button on the portable computer. An opaque member with an array of holes may be used to reduce light bleed between adjacent light-emitting diodes. Diffusing plastic may be mounted within the array of holes. Bumps in the diffusing plastic may mate with corresponding holes on a portable computer housing.

Abstract: Methods and systems for determining a state of charge of a battery are provided. A first component of the state of charge is calculated based on a first property of the battery. A second component of the state of charge is calculated based on a second property of the battery. The first component of the state of charge is weighted based on a rate of change of the first property relative to a change of the state of charge. The second component of the state of charge is weighted based on a rate of change of the second property relative to a change of the state of charge. The state of charge is determined based on the first and second weighted components.

Abstract: A system that monitors fuel cells in a fuel cell group. The system includes a plurality of voltage sensors coupled to the fuel cells in the fuel cell group, where each sensor monitors a different voltage of the fuel cells and where lower priority voltage sensors monitor higher voltages and higher priority sensors monitor lower voltages. The system also includes a plurality of oscillators where a separate oscillator is coupled to each of the sensors. Each oscillator operates at a different frequency where higher frequency oscillators are coupled to lower priority sensors and lower frequency oscillators are coupled to higher priority sensors. A light source that receives frequency signals from the oscillators and switches on and off in response to the frequency signals. A light pipe receives the switched light signals from the light source and provides light signals at a certain frequency at an end of the light pipe.

Abstract: A method of controlling a state of charge of a battery in a vehicle includes receiving a request to enter an enhanced charging mode. A target for the state of charge is increased from a normal operating target to at least one enhanced mode target. The state of charge may be controlled to the at least one enhanced mode target during a drive charging cycle and during a park charging cycle.

Abstract: The present invention is directed to a method and a system to evaluate operational characteristics of an electronic circuit. The method includes generating a visual display, on a monitor, of an eye diagram viewer. The eye diagram viewer is used to establish a test parameter for the circuit. Accessed is data that includes a graphical file containing eye diagram information corresponding to the test parameter. A visually perceivable image of the eye diagram information is provided in response to the test parameter. Specifically, the eye diagram viewer is used to establish an eye diagram information identifier by displaying in a plurality of test condition selector screens one of a multiple condition values for the test condition parameters. The graphical file containing the eye diagram information corresponding to the eye diagram information identifier is obtained from the server and displayed.

Abstract: A system and method for measuring voltage of individual cells connected in series includes a single flying capacitor. The capacitor stores the charge of one of the cells such that an analog-to-digital converter (ADC) connected to the capacitor may process an accurate representation of the voltage of the cell being measured. A plurality of switches electrically connects and disconnects the cells from the capacitor. A controller is in communication with the ADC and the switches for sequencing the switches and recording the voltage measurements of each cell. At least one precision voltage reference device is included to provide the ADC a reference voltage to provide self-calibration.

Abstract: A measuring circuit is provided for a memory integrated within a semiconductor device. The measuring circuit includes initializing means and an oscillating loop. The initializing means loadings two complementary values into at least two locations of the memory. The two locations are addressed by a first address and a second address. The oscillating loop comprises a logic circuit for alternatively generating the first address and the second address from data read from the memory so as to successively read data from the first and second memory locations to produce an oscillating signal that has a frequency that depends on internal parameters of the memory. Also provided is a method for qualifying a memory by initializing the memory by loading two complementary values into two locations, and generating an oscillating signal with a frequency that is dependent on internal parameters of the memory.

Abstract: A test system having a feedback loop that facilitates adjusting an output test waveform to a DUT/CUT (Device Under Test/Circuit Under Test) on-the-fly according to changing DUT/CUT parameters. The system includes a tester having an arbitrary waveform generator (AWG) and a data acquisition system (DAS) that monitors the status of the DUT/CUT. The AWG and DAS connect to the DUT/CUT through a feedback loop where the AWG outputs the test waveform to the DUT/CUT, the DAS monitors the DUT/CUT parameters, and the DAS analyzes and communicates changes to the AWG to effect changes in the output waveform, when desired. The AWG builds the output waveform in small slices (or segments) that are assembled together through a process of selection and calibration. The feedback architecture facilitates a number of changes in the output waveform, including a change in the original order of the preassembled slices, and changes in the magnitude/shape of the output waveform.

Abstract: A portable instrument capable of evaluating the electro-chemical deterioration of an object under test such as a multi-cell valve regulated battery (10) and comprising means capable of temporarily applying across a battery cell a controlled frequency electrical signal derived from an internal battery (11) within the instrument, the signal being an oscillatory current or voltage controlled injected signal, further means for detecting returned data resultant from the signal application, and utilizing the data and a tailored mathematical algorithm in dedicated computer software to derive the data required. Such an instrument may be used to test battery systems of the type required for uninterruptible back-up power supplies in large industrial installations.

Abstract: A method of measuring impedance is based on carrier function Laplace transform. The measurement includes detecting a response signal from a device under test, to which signal an excitation such as a pulse, interrupt or constant load is applied. Resulting data is fitted to a carrier function, selected so as to be capable of providing a good fit and for which an analytical Laplace transform is known, in order to obtain parameters of such function providing best fit. Obtained parameters are further substituted into the analytical expression of Laplace transform of carrier function which is used to calculate a frequency dependent impedance function in the Laplace domain. The resulting impedance function is used for calculating the impedance spectrum in a frequency domain and for calculating the measurement error of the frequency domain impedance spectrum using the standard deviations of the parameters, obtained during fitting of time-domain data.

Abstract: A storage battery of the conventional kind for supplying power to electrical devices has a supervising unit for determining the electric capacity. The supervising unit is electrically connected to terminal posts of the battery in order to measure the battery voltage and also measures the battery current. Measurement posts are connected to the end cells of the battery in parallel to the terminal posts and to the supervising unit through bridges. The supervising unit also measures the voltage between the measurement posts and the difference between the measured voltages is a measure of the current flowing through the battery, this difference voltage corresponding to a sum of the voltages over portions of the terminal posts and the bridges. From this difference voltage the current through the battery is calculated and therefrom the remaining electric capacity of the battery is determined by repeating regularly the measurement.

Abstract: A method and apparatus for creating, measuring and analyzing polarization voltages developed across an element, such as an electronic component or an electrochemical energy cell, or network of such elements, in response to a current mode excitation provided by a driver composed of a voltage controlled voltage source connected to one terminal of a Device Under Test and a voltage controlled current source connected to the other terminal of a Device Under Test. A voltage sensor, also connected across the Device Under Test, determines the magnitude and polarity of any potential appearing across the DUT; whenever the excitation current is exactly zero, this measured potential will be equal to the Open Circuit Potential of the DUT. This configuration of driver and sensor is known as a Kelvin connection.

Abstract: Liquid conductivity and temperature are measured in respective sensitivity fields that are collocated—i. e., in volumes that nearly match by mathematical, geometrical, or functional criteria. Collocation is as distinct from mere adjacency or proximity; and is with respect to measurement volumes, not measuring hardware. Preferably pressure too is measured with sensitivity very generally collocated to the conductivity and temperature sensitivity. Preferably, respective temporal/spatial bandwidths of the two (or three) sensors are matched. Preferably the pressure sensor is a MEMS transducer, the conductivity sensor is a four-terminal device, the thermometer is a thermistor encapsulated in a silkscreened glass wall, and circuits (1) compensate for time lag between conductivity and temperature measurement, (2) remove artifacts due to detritus in or near either sensor, and (3) derive secondary parameters of the liquid.

Abstract: A cell which has become inactive is detected in a multi-cell battery (15) comprising plural cells (Cn). An inactivity detecting circuit comprising a signal generator (Dn1) and a diode (Dn2) connected in series, is connected in parallel with the cell (Cn) When the cell becomes inactive, the signal generator (Dn1) emits a signal to indicate the state of the cell. Hence, it is possible to economically detect loss of cell activity.

Abstract: The invention includes a direct current energy source monitor which automatically detects the nominal voltage of the direct current energy source to which it is attached. The invention further includes a direct current energy source monitor which is self-powered from the direct current energy source being monitored. The multiple nominal voltage direct current energy source monitor includes an analog-to-digital converter configured to measure voltage from a direct current energy source being monitored and generate a digital output corresponding thereto. The apparatus includes a programmable control device configured to receive the digital output from the analog-to-digital converter and to look up a nominal voltage corresponding to the digital output, and is further configured to calculate a relative charge of the direct current energy source as compared to a full charge on the direct current energy source.

Abstract: In an electric battery, an electronic clock is integrated in the battery container in order to monitor battery functions. The frequency of the electronic clock is varied as a function of at least one characteristic value of the battery. In one embodiment, the frequency of the electronic clock increases with increasing electrolyte temperature and increasing deviation of the terminal voltage from the open-circuit voltage of the battery. Specifically, the electronic clock may be connected to a measurement probe immersed in the electrolyte through which voltage is supplied to the electronic clock and the battery temperature and the electrolyte level are measured. The electronic clock signals its stopping as soon as a pre-assigned nominal running time is reached.

Abstract: A battery impedance monitor includes a driver section having an oscillator which produces a pulsating loading signal which controls periodic loading of the battery to produce at its output terminals a pulsating voltage component having a peak-to-peak amplitude superimposed on the DC output voltage of the battery. This pulsating voltage component is detected in a measuring section, which applies the battery output through a voltage divider to a peak detector which outputs an indicating voltage level proportional to the peak-to-peak amplitude of the pulsating output signal, this indicating level being held on a storage capacitor. The voltage divider includes a Zener diode which shifts the DC level of the battery output without affecting the amplitude of the pulsating component.

Abstract: A method for determining whether an electrochemical cell is substantially fully charged. The determination is made by ascertaining the rate of change of the impedance of the cell with changing frequency, at low frequency. A method for determining the state of charge of an electrochemical cell by comparing the impedance of the cell at two or more frequencies or by comparing the impedance of the cell, at a medium frequency, with the impedance at high frequency. Apparatus for generating output signals representative of the magnitude of resistive and reactive components of an impedance (30). The apparatus has a signal generator (70) for passing AC current through the impedance, and a synchronous demodulator circuit (88) for demodulating AC signal appearing across the impedance pursuant to passing the current through it. A phase shift circuit (130, 132, 136, 138, 140) selectively generates control signals in phase or 90.degree.

Abstract: The present invention provides an aqueous gel comprising a polymer of (meth)acrylamide or particular (meth)acrylamide derivative(s), particulate metal oxide(s) and an aqueous medium, a process for producing said gel, and products utilizing said gel.This aqueous gel can be produced so as to have transparency, has fire resistance and can prevent the spreading of flames, and is highly elastic. The aqueous gel, when produced as a transparent gel, becomes cloudy when heated or cooled and is useful for the shielding of heat rays or cold radiation.

Abstract: A battery pack (10) has a charge measurement circuit (12) for estimating the state of charge during use. The charge measurement circuit (12) includes a sense resistor (24), amplifier (26), at least one oscillator (28), counter (30), and a communications circuit (32). The battery pack powers a host device (16), which has a limited number of modes of operation, each mode requiring a different current level. The number of oscillators (28) equals the number of modes of operation of the host device (16). As current is drawn from the battery cells (18), the sense resistor (24) and amplifier (26) act to convert the current to a voltage level. The voltage level is fed to each oscillator (28) present. Each oscillator (28) provides a clock signal at a frequency corresponding to one mode of operation of the host device, and is activated when the voltage level is within a preselected range. The clock signal is fed to a counter (30), which counts at a rate determined by the frequency of the active oscillator (28).

Abstract: A portable computer is positionable between an open condition in which an input device and an output device thereof is exposed to a user of the portable computer, and a closed condition in which the input device and the output device is protectively stowed within the portable computer, and further with the portable computer having an "on" state of operation and an "off" state of operation. The portable computer includes a battery, and a display for indicating charge levels of the battery, wherein the display is visible to the user in the open condition and in the closed condition. The portable computer further includes a mechanism for operating the display when the portable computer is in the "on" state of operation and in the "off" state of operation. Moreover, the display is operated to continuously indicate charge levels during the entire "on" state of operation as well as during the entire "off" state of operation.

Abstract: A method and apparatus for measuring the depletion level (depth of discharge) of a lithium-iodine battery in an implantable medical device. A first set of measurements are made to determine the internal impedance of the battery, and a second set of measurements are made to determine the geometric capacitance of the battery, which has been found to correlate closely to the depth of discharge of the battery. The measurements are all made while the pacemaker is first temporarily decoupled from the medical device circuitry. The first measurements are made during a time window following a known change in resistive load across the terminals of the battery, and are capable of being correlated with 1-kHz qualification testing data made on the battery at the time of manufacture. The second measurements are made when the known load is periodically coupled and decoupled to the terminals of the battery at a rate of 80-kHz.

Abstract: Nonintrusive sensors capable of measuring various storage cell parameters such as voltage, state-of-charge, electrolyte level, internal resistance, and temperature are attached to a monitoring module which gathers and processes signals representative of information concerning the condition of electrolytic storage cells and transmits the information to a central computer for further processing. In response to commands issued by the central computer, appropriate maintenance and/or repair operations can be initiated. Alternatively, the system described can be used to automatically perform such maintenance tasks as checking and adding electrolyte levels, reducing the voltage in cells whose output voltage is too high, and leveling the state-of-charge of each cell in an array of electrolytic storage cells. The system can monitor other functions of the electrolytic storage cells, including the evolution of hydrogen gas and the accumulation of sediments in individual electrolytic storage cells.

Abstract: A thermostat having a simple battery level detection circuit. The output of an oscillator, having a frequency dependent upon the battery level, is compared to the output of a battery level independent time base. If the two outputs are not in a predetermined relationship, all connected HVAC equipment is shut off.

Abstract: The portable information apparatus has a battery, a boosting circuit for boosting a voltage of the battery, a battery voltage detector for detecting a voltage level of the battery, an oscillating circuit for generating CPU clock and a counting circuit for counting the interval from the start of the oscillation of the CPU clock to the time when it becomes stable. The apparatus negates the output of the battery voltage detector during the interval counted by the counting circuit so that it can prevent the monitoring of the battery voltage lowering in the time of usual performance from influencing of the battery potential drop due to the transient current at the start of the performance of the boosting circuit and the oscillating circuit.

Abstract: Method and apparatus for measuring the voltage and state of charge of a secondary battery. The voltage and state of charge values are taken by a circuit every four (4) seconds by reading voltage, waiting two (2) seconds, reading current, waiting two (2) seconds, and repeating the voltage readings and the current readings. The circuit includes a 4-bit microprocessor, CMOS analog switches, and two operational amplifiers. The voltage and current readings are taken from dual-sloped converters, and the values determined by software algorithms in the microprocessor.

Abstract: A self-contained electronic device instantaneously assesses the stored energy capacity of single, two-volt, lead-acid cells; or of batteries comprised of such cells. The testing device is electrically connected to the terminals of a cell or battery and measures its dynamic conductance with a small, time-varying signal. An internal conductance standard permits initial calibration of the device to assure accuracy of the cell/battery measurements. Means are provided for entering a "reference conductance", defined to be the dynamic conductance of an identically rated and constructed cell or battery having 100% energy capacity. The device displays either the test cell/battery's measured conductance in Siemens (mhos), or its "percent capacity" determined by appropriately scaling its measured conductance in accordance with the "reference conductance". When determining "percent capacity", an LED lights if the result is less than a preset threshold value.

Abstract: Monitoring state of charge of an electric storage battery (18) is done by deliberately inducing eddy currents, specifically using an induction coil (70) in conductive metallic constituents of negative plate material (74) of the battery concerned, and detecting effects representative of said eddy currents, specifically by detecting (76, 78) amplitude or frequency effects on energizing signals (72).

Abstract: Apparatus for measuring the total internal resistance of a multicell battery having positive and negative terminals employs a first transistor device having an input and an output and having mutually exclusive conductive and non-conductive electric states. An arrangement of resistances is connected in series with the device to form a network. The network is connected between the positive and negative terminals. An operational amplifier has an output connected to the input of the device and first and second inputs. The first input is connected to the network at a point connected to both of the device and the arrangement. A square wave signal alternating between a positive voltage and ground on alternate half cycles is applied to the second input. The device is in the conductive state when the alternating voltage is positive and is in the non-conductive state when the alternating voltage is at ground.

Abstract: A battery monitors by which an individual cell in a wet cell battery may be monitored for variations in the level of electrolyte contained in the cell. More specifically, the invention relates to a universal electrolyte level indicator which may be attached to, and made part of, battery powered mobile equipment of all types for the purposes of providing a warning indication to the operator of the equipment that water needs to be added to the batteries contained therein.

Abstract: A battery monitors by which an individual cell in a wet cell battery may be monitored for variations in the level of electrolyte contained in the cell. More specifically, the invention relates to a universal electrolyte level indicator which may be attached to, and made part of, battery powered mobile equipment of all types for the purposes of providing a warning indication to the operator of the equipment that water needs to be added to the batteries contained therein.

Abstract: The invention provides an apparatus for controlling both the supersaturation of the mother liquor and the crystal content of massecuite by measuring di-electric constant and electrical conductivity at radio frequencies by means of a probe which is included in a circuit which may be tuned to a fixed setting or may be variably tuned, the combined impedance is measured as a function of the tuning and the measurements are compared with predetermined desired values. By suitable combination of the two signals, measurement of crystal content and mother liquor supersaturation can be controlled.

Abstract: A self-contained electronic device for testing disparate storage batteries having any one of a fixed plurality of possible nominal voltages is disclosed. The testing device performs small-signal measurements of a battery's dynamic conductance and provides either a proportional numerical readout, displayed in appropriate battery measuring units, or a corresponding qualitative assessment of the battery's relative condition. Special voltage-sensing circuitry within the testing device identifies the particular one of the possible nominal voltages possessed by the battery and scales the dynamic conductance measurements accordingly. As a result, the quantitative or qualitative information provided to the user is automatically adjusted to comport with the nominal voltage of the battery undergoing test without the user having to actually input the battery's nominal voltage to the testing device.

Abstract: An improved self-contained electronic device for testing storage batteries and other dc sources is disclosed. The testing device accurately performs small-signal measurements of the battery's dynamic conductance and provides for displaying either a numerical reading proportional to the battery's available power, or a qualitative assessment of the battery's condition. Special design features permit powering all active circuit elements by means of common power terminals and allow circuit implementation with medium scale integrated (MSI) circuits.

Abstract: A condition tester for a storage battery that monitors the effect of internal battery resistance without drawing large currents. A switched load periodically draws a small current across the battery terminals. An AC voltage is produced at the battery terminals resulting from the oscillating current and the internal battery resistance. That small oscillating voltage is amplified, rectified and filtered to produce a DC voltage which depends upon the AC component. This DC voltage is subtracted from the nominal battery voltage and the difference is indicated by an appropriate meter. As the battery deteriorates its internal resistance increases causing the meter reading to decrease, thereby reflecting battery condition.

Abstract: A lithium battery is provided with an energy monitor that continuously inates the energy remaining in the battery. An electrolytic coulometer is connected in series with the battery and has a cantilevered cathode which increases its mass in proportion to the total amount of current that flows from the battery. Since the mass of the cathode and hence its resonant frequency changes in proportion to the total current, a mechanical transducer in contact with the electrolytic coulometer causes the cantilevered cathode to resonate at different frequencies which is monitored to provide a continuous reading of remaining battery energy.

Abstract: A method and apparatus for measuring the remaining charge of a galvanic cell effects the measurement of the remaining charge by superimposing an AC voltage or current on DC voltage or current issuing from the cell to produce a higher harmonic current or voltage, determining the value corresponding to a higher harmonic component of n'th order from the higher harmonic current or voltage, and comparing the value thus measured of the cell under test with that measured previously in the same manner of a reference galvanic cell. Since the corresponding value of the higher harmonic current or voltage of n'th order varies notably with the decrease in the remaining charge of the galvanic cell, the comparison of the found corresponding value with the reference characteristic is effected with ease and the measurement can be carried out accurately and simply.

Abstract: The system includes a digital integrator having a plurality of digital stages operable to store a numerical value in binary digital form which is indicative of state of charge. A switching circuit is provided for generating a series of voltage pulses on a single output line with each pulse corresponding in length to the binary digital value stored in the integrator to provide a time based resultant indication of the stored binary digital value. A filtering means is included to provide a substantially smooth analog output voltage having an amplitude corresponding to the summation of the pulses.The system preferably includes a delayed high voltage reset feature to set the integrator to a full charge state in response to voltage levels accompanying charging of the battery.

Abstract: A low charge detector, for a measuring instrument incorporating a meter for indicating measurement readings, includes a "low battery detector" circuit which causes a first output to be released from a 1 Hz oscillator, when a battery pack supplying power to the instrument discharges to a predetermined level. The first output is then applied to a pointer on the meter, thus causing the pointer to execute oscillations of a relatively small amplitude.When the battery pack is substantially dead, a "dead battery detector" circuit causes a second output to be released from the oscillator and to combine with the first output. The combined output is then applied to the pointer, thus causing the pointer to execute oscillations of a substantially greater amplitude, thereby indicating that recharging of the battery pack is required.

Abstract: A battery tester apparatus having a discharge circuit with a visual indicator that the discharge cycle is in progress operating in combination with a comparator to determine when the terminal voltage of the battery is reached. At this point the comparator provides a signal to an oscillator which in turn controls an SCR diode switch that terminates the discharge cycle.